U.S. patent number 7,254,702 [Application Number 11/031,509] was granted by the patent office on 2007-08-07 for method of distributed recording whereby the need to transition to a second recording device from a first recording device is broadcast by the first recording device.
This patent grant is currently assigned to Sony Corporation, Sony Electronics, Inc.. Invention is credited to Bruce Alan Fairman, Scott David Smyers, Glen David Stone, Thomas Ulrich Swidler.
United States Patent |
7,254,702 |
Swidler , et al. |
August 7, 2007 |
Method of distributed recording whereby the need to transition to a
second recording device from a first recording device is broadcast
by the first recording device
Abstract
An automatically configuring storage array includes a plurality
of media storage devices coupled together within a network of
devices. Preferably, the network of devices is an IEEE 1394-2000
serial bus network of devices. The media storage devices are
utilized to record and retrieve streams of data transmitted within
the network of devices. The media storage devices communicate with
each other in order to store and retrieve streams of data over
multiple media storage devices, if necessary. When a record or
playback command is received by any one of the media storage
devices, the media storage devices send control communications
between themselves to ensure that the stream of data is recorded or
transmitted, as appropriate. Control of the record or transmit
operation is also transferred between the media storage devices in
order to utilize the full capacity of the available media storage
devices. Preferably, streams of data are recorded utilizing
redundancy techniques. An internal file system is included within
each media storage device. A file table associated with each
recorded stream of data is stored within the internal file system
of each media storage device to facilitate search and retrieval of
the recorded streams of data throughout the media storage devices.
Preferably, the media storage devices accept control instructions
directly from devices within the network. Alternatively, a control
device is utilized to provide a control interface between the media
storage devices and the other devices within the network.
Inventors: |
Swidler; Thomas Ulrich (San
Jose, CA), Fairman; Bruce Alan (Woodside, CA), Stone;
Glen David (Los Gatos, CA), Smyers; Scott David (San
Jose, CA) |
Assignee: |
Sony Corporation (Tokyo,
JP)
Sony Electronics, Inc. (Park Ridge, NJ)
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Family
ID: |
26977628 |
Appl.
No.: |
11/031,509 |
Filed: |
January 7, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050125569 A1 |
Jun 9, 2005 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10210928 |
Aug 2, 2002 |
6859846 |
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09861825 |
May 21, 2001 |
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09310876 |
Jun 12, 2001 |
6247069 |
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Current U.S.
Class: |
713/1; 709/231;
710/8; 711/114; 711/132; 711/170; 713/2 |
Current CPC
Class: |
G06F
3/0605 (20130101); G06F 3/0629 (20130101); G06F
3/0659 (20130101); G06F 3/0689 (20130101); H04L
12/40058 (20130101); H04L 12/40117 (20130101); G06F
3/0613 (20130101); G06F 3/0643 (20130101); G06F
3/067 (20130101) |
Current International
Class: |
G06F
11/00 (20060101) |
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Primary Examiner: Elamin; A.
Attorney, Agent or Firm: Haverstock & Owens LLP
Parent Case Text
RELATED APPLICATIONS
This Patent Application is a continuation of U.S. patent
application Ser. No. 10/210,928, filed on Aug. 2, 2002 now U.S.
Pat. No. 6,859,846 and entitled A METHOD OF DISTRIBUTED RECORDING
WHEREBY THE NEED TO TRANSITION TO A SECOND RECORDING DEVICE FROM A
FIRST RECORDING DEVICE IS BROADCAST BY THE FIRST RECORDING DEVICE,
which is a continuation-in-part of U.S. patent application Ser. No.
09/861,825, filed on May 21, 2001 and entitled AUTOMATICALLY
CONFIGURING STORAGE ARRAY INCLUDING A PLURALITY OF MEDIA STORAGE
DEVICES FOR STORING AND PROVIDING DATA WITHIN A NETWORK OF DEVICES,
which is a continuation of application Ser. No. 09/310,876, filed
May 12, 1999, now issued U.S. Pat. No. 6,247,069, issued on Jun.
12, 2001 and entitled AUTOMATICALLY CONFIGURING STORAGE ARRAY
INCLUDING A PLURALITY OF MEDIA STORAGE DEVICES FOR STORING AND
PROVIDING DATA WITHIN A NETWORK OF DEVICES. The U.S. patent
application Ser. No. 10/210,928, filed on Aug. 2, 2002 and entitled
A METHOD OF DISTRIBUTED RECORDING WHEREBY THE NEED TO TRANSITION TO
A SECOND RECORDING DEVICE FROM A FIRST RECORDING DEVICE IS
BROADCAST BY THE FIRST RECORDING DEVICE, the U.S. patent
application Ser. No. 09/861,825, filed on May 21, 2001 and entitled
AUTOMATICALLY CONFIGURING STORAGE ARRAY INCLUDING A PLURALITY OF
MEDIA STORAGE DEVICES FOR STORING AND PROVIDING DATA WITHIN A
NETWORK OF DEVICES and issued U.S. Pat. No. 6,247,069, issued on
Jun. 12, 2001 and entitled AUTOMATICALLY CONFIGURING STORAGE ARRAY
INCLUDING A PLURALITY OF MEDIA STORAGE DEVICES FOR STORING AND
PROVIDING DATA WITHIN A NETWORK OF DEVICES are also hereby
incorporated by reference.
Claims
What is claimed is:
1. A method of recording data within an automatically configuring
storage array including a plurality of media storage devices
comprising: a. receiving a record command to record a stream of
data within the array; b. recording the stream of data on media
within one or more media storage devices within the array, thereby
forming a recorded stream of data; and c. recording a file table
associated with the recorded stream of data, wherein the file table
includes identifying and pointing information about the recorded
stream of data.
2. The method as claimed in claim 1 wherein control communications
are sent to identify a next available media storage device when
recording responsibility is transferred from a current recording
media storage device to the next available media storage
device.
3. The method as claimed in claim 1 wherein control communications
and the stream of data are sent over a serial bus that
substantially complies with an IEEE 1394 standard.
4. The method as claimed in claim 1 wherein each media storage
device that stores a portion of the recorded stream of data
includes the file table associated with the portion of the recorded
stream of data stored on that media storage device.
5. The method as claimed in claim 4 wherein the identifying and
pointing information within the file table includes a correlation
between each frame within the portion of the recorded stream of
data and a storage location of the frame within the media storage
device, a location of a previously recorded portion of the recorded
stream of data, and a location of a subsequently recorded portion
of the recorded stream of data.
6. The method as claimed in claim 1 wherein the record command is
received from a remote controller.
7. The method as claimed in claim 1 wherein the stream of data is
transmitted on a data isochronous channel.
8. The method as claimed in claim 1 further comprising recording
redundant information regarding the stream of data which is used to
reconstruct lost data within the recorded stream of data.
9. The method as claimed in claim 1 wherein each frame within the
recorded stream of data is identified by the elapsed time from the
start of the recorded stream of data to the frame, wherein the
elapsed time is measured in hours, minutes, seconds and frames.
10. A method of recording data within an automatically configuring
storage array including a plurality of media storage devices
comprising: a. receiving a record command to record a stream of
data within the array; b. recording the stream of data on media
within one or more media storage devices within the array, thereby
forming a recorded stream of data; and c. recording a file table
associated with the recorded stream of data, wherein the file table
includes identifying and pointing information about the recorded
stream of data; wherein each media storage device that stores a
portion of the recorded stream of data includes the file table
associated with the portion of the recorded stream of data stored
on that media storage device.
11. The method as claimed in claim 10 wherein control
communications are sent to identify the next available media
storage device when recording responsibility is transferred from a
current recording media storage device to the next available media
storage device.
12. The method as claimed in claim 10 wherein the control
communications and the stream of data are sent over a serial bus
that substantially complies with an IEEE 1394 standard.
13. The method as claimed in claim 10 wherein the identifying and
pointing information within the file table includes a correlation
between each frame within the portion of the recorded stream of
data and that frames' storage location within the media storage
device, a location of a previously recorded portion of the recorded
stream of data, and a location of a subsequently recorded portion
of the recorded stream of data.
14. A storage array within a network of devices including data
source devices and data reception devices, the automatically
configuring storage array including a plurality of media storage
devices having ability to record a received stream of data, thereby
forming a recorded stream of data, wherein each media storage
device that stores a portion of the recorded stream of data
includes a file table associated with the portion of the recorded
stream of data for identifying and pointing to portions of the
recorded stream of data stored on different media storage
devices.
15. The automatically configuring storage array as claimed in claim
14 wherein the file table associated with the portion of the
recorded stream of data includes a correlation between each frame
within the portion of the recorded stream of data and a storage
location of the frame within the media storage device, a location
of a previously recorded portion of the recorded stream of data,
and a location of a subsequently recorded portion of the recorded
stream of data.
16. The automatically configuring storage array as claimed in claim
14 wherein the recorded stream of data is recorded utilizing
redundancy recording techniques.
17. The automatically configuring storage array as claimed in claim
14 further comprising a controller coupled to the media storage
devices to initiate record and transmit operations.
18. The automatically configuring storage array as claimed in claim
14 wherein the media storage devices include one or more hard disk
drives.
19. The automatically configuring storage array as claimed in claim
14 wherein the automatically configuring storage array is formed
within a serial bus network of devices that substantially complies
with an IEEE 1394 standard.
20. A network of devices comprising: a. a source device for
providing a stream of data; and b. a storage array coupled to the
source device, the storage array including a plurality of media
storage devices having ability to record the received stream of
data, thereby forming a recorded stream of data, wherein each media
storage device that stores a portion of the recorded stream of data
includes a file table associated with the portion of the recorded
stream of data for identifying and pointing to portions of the
recorded stream of data stored on different media storage
devices.
21. The network of devices as claimed in claim 20 wherein the file
table associated with the portion of the recorded stream of data
includes a correlation between each frame within the portion of the
recorded stream of data and a storage location of the frame within
the media storage device, a location of a previously recorded
portion of the recorded stream of data, and a location of a
subsequently recorded portion of the recorded stream of data.
22. The network of devices as claimed in claim 20 wherein the
recorded stream of data is recorded utilizing redundancy recording
techniques.
23. The network of devices as claimed in claim 20 further
comprising a controller coupled to the media storage devices to
initiate record and transmit operations.
24. The network of devices as claimed in claim 20 wherein the media
storage devices include one or more hard disk drives.
25. The network of devices as claimed in claim 20 wherein the
network of devices is formed by a serial bus network of devices
that substantially complies with an IEEE 1394 standard.
26. A distributed file table representing storage locations
corresponding to a recorded stream of data, the distributed file
table including one or more file tables, wherein each file table is
associated with a portion of the recorded stream of data stored on
one of a plurality of media storage devices within a network of
devices and includes identifying information about the portion of
the recorded stream of data on the media storage device and
pointing information about other portions of the recorded stream of
data on different media storage devices, further wherein each file
table is maintained by and recorded onto the media storage device
on which the associated portion of the recorded stream of data is
recorded.
27. The distributed file table as claimed in claim 26 wherein the
file table associated with the portion of the recorded stream of
data includes a correlation between each frame within the portion
of the recorded stream of data and a storage location of the frame
within the media storage device, a location of a previously
recorded portion of the recorded stream of data, and a location of
a subsequently recorded portion of the recorded stream of data.
28. The distributed file table as claimed in claim 26 further
comprising a controller coupled to the media storage device to
maintain and record the information included within the file table
corresponding to the media storage device.
Description
FIELD OF THE INVENTION
The present invention relates to the field of writing data to and
reading data from media storage devices. More particularly, the
present invention relates to the field of writing data to and
reading data from media storage devices within a network of
devices.
BACKGROUND OF THE INVENTION
The IEEE 1394-2000 standard, "1394 Standard For A High Performance
Serial Bus," is an international standard for implementing an
inexpensive high-speed serial bus architecture which supports both
asynchronous and isochronous format data transfers. In addition,
the IEEE 1394-2000 bus has a universal clock called the cycle
timer. This clock is synchronized on all nodes. Isochronous data
transfers are real-time transfers which take place based on the
universal clock such that the time intervals between significant
instances have the same duration at both the transmitting and
receiving applications. Each packet of data transferred
isochronously is transferred in its own time period. An example of
an ideal application for the transfer of data isochronously would
be from a video recorder to a television set. The video recorder
records images and sounds and saves the data in discrete chunks or
packets. The video recorder then transfers each packet,
representing the image and sound recorded over a limited time
period, during that time period, for display by the television set.
The IEEE 1394-2000 standard bus architecture provides multiple
independent channels for isochronous data transfer between
applications. A six bit channel number is broadcast with the data
to ensure reception by the appropriate application. This allows
multiple applications to simultaneously transmit isochronous data
across the bus structure. Asynchronous transfers are traditional
reliable data transfer operations which take place as soon as
arbitration is won and transfer a maximum amount of data from a
source to a destination.
The IEEE 1394-2000 standard provides a high-speed serial bus for
interconnecting digital devices thereby providing a universal I/O
connection. The IEEE 1394-2000 standard defines a digital interface
for the application thereby eliminating the need for an application
to convert digital data to analog data before it is transmitted
across the bus. Correspondingly, a receiving application will
receive digital data from the bus, not analog data, and will
therefore not be required to convert analog data to digital data.
The cable required by the IEEE 1394-2000 standard is very thin in
size compared to other bulkier cables used to connect such devices
in other connection schemes. Devices can be added and removed from
an IEEE 1394-2000 bus while the bus is operational. If a device is
so added or removed the bus will then automatically reconfigure
itself for transmitting data between the then existing nodes. A
node is considered a logical entity with a unique address on the
bus structure. Each node provides in a standard address space, an
identification ROM, a standardized set of control registers and in
addition, its own address space.
The IEEE 1394-2000 standard defines a protocol as illustrated in
FIG. 1. This protocol includes a serial bus management block 10
coupled to a transaction layer 12, a link layer 14 and a physical
layer 16. The physical layer 16 provides the electrical and
mechanical connection between a device and the IEEE 1394-2000
cable. The physical layer 16 also provides arbitration to ensure
that all devices coupled to the IEEE 1394-2000 bus have arbitrated
access to the bus as well as actual data transmission and
reception. The link layer 14 provides data packet delivery service
for both asynchronous and isochronous data packet transport. This
supports both asynchronous data transport, using an acknowledgment
protocol, and isochronous data transport, providing an
un-acknowledged real-time guaranteed bandwidth protocol for
just-in-time data delivery. The transaction layer 12 supports the
commands necessary to complete asynchronous data transfers,
including read, write and lock. The serial bus management block 10
contains an isochronous resource manager for managing the resources
associated with isochronous data transfers. The serial bus
management block 10 also provides overall configuration control of
the serial bus in the form of optimizing arbitration timing,
guarantee of adequate electrical power for all devices on the bus,
assignment of the cycle master, assignment of isochronous channel
and bandwidth resources and basic notification of errors.
The AV/C Command Set is a command set used for transactions to and
from consumer audio/video equipment over an IEEE 1394-2000 serial
bus. This AV/C command set makes use of the Function Control
Protocol (FCP) defined by IEC-61883, the ratified international
standard for the transport of audio/video command requests and
responses. AV/C commands are transmitted through AV/C transactions.
An AV/C transaction consists of one AV/C command frame addressed to
the target node's FCP_Command register and zero or more AV/C
response frames addressed to the requesting node's FCP_Response
register.
Each audio/video unit or subunit can implement a subset of the AV/C
command set. An unsupported command received by an audio/video unit
is rejected with a not implemented response. Support for the
different commands is characterized as mandatory, recommended,
optional and vendor-dependent. A mandatory command is supported by
any audio/video device that claims compliance with the AV/C command
set and that implements the audio/video unit or subunit type for
which the command is defined. An AV/C compliant device is
identified by an entry within its configuration read-only memory
(ROM). A recommended command is optional for an AV/C compliant
device, but represents a basic functionality, such as video and
audio insert modes for a VCR subunit's record command. If the
device supports a unit or subunit type that has the functionality
corresponding to the command, it is recommended that the command be
implemented. An optional command is optional for an AV/C compliant
device. Support for and interpretation of a vendor-dependent
command are defined by the device vendor.
AV/C commands are grouped into four command types including
control, status, inquiry and notify command types. A control
command is sent by a controller to another audio/video device, the
target, to instruct the target to perform an operation. A target
that receives a control command will return an AV/C response frame
including either a not implemented, accepted, rejected or interim
response code. The target will return a not implemented response
code when the target does not support the control command specified
or the command is addressed to a subunit not implemented by the
target. The target will return an accepted response code when the
target implements the control command specified and the current
state of the target permits execution of the command. The target
will return a rejected response code when the target implements the
control command specified but the current state of the target does
not permit execution of the command. The target will return an
interim response code if the control command specified is
implemented by the target, but the target is unable to respond with
either an accepted or rejected response code within 100
milliseconds. Unless a subsequent bus reset causes the AV/C
transaction to be aborted, the target will ultimately return a
response frame with an accepted or rejected response code after
returning an interim response code.
A status command is sent by a controller to an audio/video device
to request the current status of the target device. Status commands
may be sent to either audio/video units or subunits. A target that
receives a status command will return an AV/C response frame
including either a not implemented, rejected, in transition or
stable response code. A target will return a not implemented status
response code when the target does not support the status command
specified or the command is addressed to a subunit not implemented
by the target. A target will return a rejected status response code
when the target implements the status command specified but the
target state does not permit the return of status for the command.
The target will return an in transition status response code when
the target implements the status command specified, but the current
state of the target is in transition. The target will return a
stable status response code when the target implements the status
command specified and the information requested is reported in the
values in the AV/C response frame.
An inquiry command is used by a controller to determine whether or
not a target audio/video device supports a particular control
command. A controller can reliably use inquiry commands to probe
the capabilities of a target, since the target shall not modify any
state nor initiate any command execution in response to an inquiry
command. A target that receives an inquiry command will return an
AV/C response frame including either an implemented or a not
implemented response code. An implemented response code notifies
the controlling node that the corresponding control command
specified is implemented by the target audio/video device. A not
implemented response code notifies the controlling node that the
corresponding control command specified is implemented by the
target audio/video device.
A notify command is used by a controller to receive notification of
future changes in an audio/video device's state. Responses to a
notify command will indicate the current state of the target and
then, at some indeterminate time in the future, indicate the
changed state of the target. A target that receives a notify
command will return an immediate response frame including either a
not implemented, rejected or interim response code. A target will
return a not implemented response code when the target does not
support the notify command specified or the command is addressed to
a subunit not implemented by the target. A target will return a
rejected response code when the target implements event
notification for the condition specified but is not able to supply
the requested information. A target will return an interim response
code when the target supports the requested event notification and
has accepted the notify command for any future change of state. The
current state is indicated by the data returned in the response
frame. At a future time, the target will then return an AV/C
response frame with either a rejected or changed response code.
A traditional hard disk drive records data and plays it back
according to commands received from an external controller using a
protocol such as the serial bus protocol (SBP). The external
controller provides command data structures to the hard disk drive
which inform the hard disk drive where on the media the data is to
be written, in the case of a write application, or read from, in
the case of a read operation.
Use of a media storage device, such as a hard disk drive, for
storing streams of audio and video data is taught in U.S. patent
application Ser. No. 09/022,926, filed on Feb. 12, 1998 and
entitled "MEDIA STORAGE DEVICE WITH EMBEDDED DATA FILTER FOR
DYNAMICALLY PROCESSING DATA DURING READ AND WRITE OPERATIONS,"
which is hereby incorporated by reference. When storing audio and
video data streams on such a hard disk drive, the available
capacity of the device can be quickly utilized, due to the large
amounts of data included in typical audio and video data streams.
If multiple traditional hard disk drives are utilized to store
large streams of data, then the user must typically be responsible
for management of these storage and retrieval procedures. This
storage management responsibility adds complexity to operations
such as record and playback and requires the user to monitor and
control storage and retrieval operations.
SUMMARY OF THE INVENTION
An automatically configuring storage array includes a plurality of
media storage devices coupled together within a network of devices.
Preferably, the network of devices is an IEEE 1394-2000 serial bus
network of devices. The media storage devices are utilized to
record and retrieve streams of data transmitted within the network
of devices. The media storage devices communicate with each other
in order to store and retrieve streams of data over multiple media
storage devices, if necessary. When a record or playback command is
received by any one of the media storage devices, the media storage
devices send control communications between themselves to ensure
that the stream of data is recorded or transmitted, as appropriate.
Control of the record or transmit operation is also transferred
between the media storage devices in order to utilize the full
capacity of the available media-storage devices. Preferably,
streams of data are recorded utilizing redundancy techniques. An
internal file system is included within each media storage device.
A file table associated with each recorded stream of data is stored
within the internal file system of each media storage device to
facilitate search and retrieval of the recorded streams of data
throughout the media storage devices. Preferably, the media storage
devices accept control instructions directly from devices within
the network. Alternatively, a control device is utilized to provide
a control interface between the media storage devices and the other
devices within the network.
In one aspect of the present invention, a method of recording data
within an automatically configuring storage array including a
plurality of media storage devices includes receiving a record
command to record a stream of data at one of the media storage
devices, determining a next available media storage device
independent of the record command, recording the stream of data on
media within the next available media storage device, thereby
forming a recorded stream of data, recording a file table
associated with the recorded stream of data within the next
available media storage device, wherein the file table includes
identifying and pointing information about the recorded stream of
data, sending control communications from the next available media
storage device to other media storage devices within the
automatically configuring storage array, and repeating the above
process when the next available media storage device does not have
capacity to record remaining portions of the stream of data, until
the stream of data is fully recorded. Control communications are
sent to identify the next available media storage device when
recording responsibility is transferred from a current recording
media storage device to the next available media storage device.
The control communications and the stream of data are sent over a
serial bus that substantially complies with an IEEE 1394 standard.
Each media storage device that stores a portion of the recorded
stream of data includes the file table associated with the portion
of the recorded stream of data stored on that media storage device.
The identifying and pointing information within the file table
includes a correlation between each frame within the portion of the
recorded stream of data and a storage location of the frame within
the media storage device, a location of a previously recorded
portion of the recorded stream of data, and a location of a
subsequently recorded portion of the recorded stream of data.
Determining the next available media storage device is performed by
sending a broadcast message to the plurality of media storage
devices requesting response from each media storage device that has
available storage capacity and selecting the next available media
storage device from those media storage devices that respond to the
broadcast message. The next available media storage device is
selected from the media storage devices that respond to the
broadcast message based on the media storage device that has the
most available storage capacity. The next available media storage
device is selected from the media storage devices that respond to
the broadcast message based on the media storage device that is a
first to respond to the broadcast message. The record command is
received from a remote controller. The stream of data is
transmitted on a data isochronous channel. The control
communications include a real time component transmitted on a
control isochronous channel. The control communications include a
non-real time component transmitted by asynchronous commands. The
method further includes recording redundant information regarding
the stream of data which is used to reconstruct lost data within
the recorded stream of data. Each frame within the recorded stream
of data is identified by the elapsed time from the start of the
recorded stream of data to the frame, wherein the elapsed time is
measured in hours, minutes, seconds and frames.
In another aspect of the present invention, a method of recording
data within an automatically configuring storage array including a
plurality of media storage devices includes receiving a record
command to record a stream of data at one of the media storage
devices, determining a next available media storage device
independent of the record command, recording the stream of data on
media within the next available media storage device, thereby
forming a recorded stream of data, recording a file table
associated with the recorded stream of data within the next
available media storage device, wherein the file table is stored on
and maintained by the next available media storage device and
includes identifying and pointing information about the recorded
stream of data, sending control communications from the next
available media storage device to other media storage devices
within the automatically configuring storage array, and repeating
the above process when the next available media storage device does
not have capacity to record remaining portions of the stream of
data, until the stream of data is fully recorded, wherein each
media storage device that stores a portion of the recorded stream
of data includes the file table associated with the portion of the
recorded stream of data stored on that media storage device.
Control communications are sent to identify the next available
media storage device when recording responsibility is transferred
from a current recording media storage device to the next available
media storage device The control communications and the stream of
data are sent over a serial bus that substantially complies with an
IEEE 1394 standard. The identifying and pointing information within
the file table includes a correlation between each frame within the
portion of the recorded stream of data and that frames' storage
location within the media storage device, a location of a
previously recorded portion of the recorded stream of data, and a
location of a subsequently recorded portion of the recorded stream
of data. Determining the next available media storage device is
performed by sending a broadcast message to the plurality of media
storage devices requesting response from each media storage device
that has available storage capacity and selecting the next
available media storage device from those media storage devices
that respond to the broadcast message. The next available media
storage device is selected from the media storage devices that
respond to the broadcast message based on the media storage device
that has the most available storage capacity. The next available
media storage device is selected from the media storage devices
that respond to the broadcast message based on the media storage
device that is a first to respond to the broadcast message.
In yet another aspect of the present invention, an automatically
configuring storage array within a network of devices including
data source devices and data reception devices, the automatically
configuring storage array including a plurality of distributed
intelligent media storage devices having ability to automatically
configure themselves and record a received stream of data over
multiple media storage devices, thereby forming a recorded stream
of data, wherein each media storage device that stores a portion of
the recorded stream of data includes a file table associated with
the portion of the recorded stream of data for identifying and
pointing to portions of the recorded stream of data stored on
different media storage devices. The file table associated with the
portion of the recorded stream of data includes a correlation
between each frame within the portion of the recorded stream of
data and a storage location of the frame within the media storage
device, a location of a previously recorded portion of the recorded
stream of data, and a location of a subsequently recorded portion
of the recorded stream of data. The recorded stream of data is
recorded utilizing redundancy recording techniques. The
automatically configuring storage array can further include a
controller coupled to the media storage devices to initiate record
and transmit operations. The media storage devices include one or
more hard disk drives. The automatically configuring storage array
is formed within a serial bus network of devices that substantially
complies with an IEEE 1394 standard.
In still yet another aspect of the present invention, an
automatically configuring storage array within a network of devices
including data source devices and data reception devices, the
automatically configuring storage array including a plurality of
distributed intelligent media storage devices having ability to
automatically configure themselves and record a received stream of
data over multiple media storage devices, thereby forming a
recorded stream of data, and to automatically retrieve and playback
the recorded stream of data, wherein each media storage device that
stores a portion of the recorded stream of data includes a file
table associated with the portion of the recorded stream of data
for identifying and pointing to portions of the recorded stream of
data stored on different media storage devices. The file table
associated with the portion of the recorded stream of data includes
a correlation between each frame within the portion of the recorded
stream of data and a storage location of the frame within the media
storage device, a location of a previously recorded portion of the
recorded stream of data, and a location of a subsequently recorded
portion of the recorded stream of data. The recorded stream of data
is recorded utilizing redundancy recording techniques. The
automatically configuring storage array can further include a
controller coupled to the media storage devices to initiate record,
playback and transmit operations. The media storage devices include
one or more hard disk drives. The automatically configuring storage
array is formed within a serial bus network of devices that
substantially complies with an IEEE 1394 standard.
In other aspect of the present invention, a method of recording
data within an automatically configuring storage array including a
plurality of media storage devices includes receiving a record
command to record a stream of data at one of the media storage
devices, determining a next available media storage device
independent of the record command by sending a broadcast message to
the plurality of media storage devices requesting response from
each media storage device that has available storage capacity and
selecting the next available media storage device from those media
storage devices that respond to the broadcast message, recording
the stream of data on media within the next available media storage
device, thereby forming a recorded stream of data, recording a file
table associated with the recorded stream of data within the next
available media storage device, wherein the file table includes
identifying and pointing information about the recorded stream of
data, sending control communications from the next available media
storage device to other media storage devices within the
automatically configuring storage array, and repeating the above
process when the next available media storage device does not have
capacity to record remaining portions of the stream of data, until
the stream of data is fully recorded. The next available media
storage device is selected from the media storage devices that
respond to the broadcast message based on the media storage device
that has the most available storage capacity. The next available
media storage device is selected from the media storage devices
that respond to the broadcast message based on the media storage
device that is a first to respond to the broadcast message.
In a further aspect of the present invention, a network of devices
includes a source device for providing a stream of data, and an
automatically configuring storage array coupled to the source
device, the automatically configuring storage array including a
plurality of distributed intelligent media storage devices having
ability to automatically configure themselves and record the
received stream of data over multiple media storage devices,
thereby forming a recorded stream of data, wherein each media
storage device that stores a portion of the recorded stream of data
includes a file table associated with the portion of the recorded
stream of data for identifying and pointing to portions of the
recorded stream of data stored on different media storage devices.
The file table associated with the portion of the recorded stream
of data includes a correlation between each frame within the
portion of the recorded stream of data and a storage location of
the frame within the media storage device, a location of a
previously recorded portion of the recorded stream of data, and a
location of a subsequently recorded portion of the recorded stream
of data. The recorded stream of data is recorded utilizing
redundancy recording techniques. The network of devices can further
include a controller coupled to the media storage devices to
initiate record and transmit operations. The media storage devices
include one or more hard disk drives. The network of devices is
formed by a serial bus network of devices that substantially
complies with an IEEE 1394 standard.
In another aspect of the present invention, a distributed file
table representing storage locations corresponding to a recorded
stream of data, the distributed file table including one or more
file tables, wherein each file table is associated with a portion
of the recorded stream of data stored on one of a plurality of
distributed intelligent media storage devices within a network of
devices and includes identifying information about the portion of
the recorded stream of data on the media storage device and
pointing information about other portions of the recorded stream of
data on different media storage devices, further wherein each file
table is maintained by and recorded onto the media storage device
on which the associated portion of the recorded stream of data is
recorded. Each file table associated with the portion of the
recorded stream of data includes a correlation between each frame
within the portion of the recorded stream of data and a storage
location of the frame within the media storage device, a location
of a previously recorded portion of the recorded stream of data,
and a location of a subsequently recorded portion of the recorded
stream of data. The distributed file table can further include a
controller coupled to the media storage device to maintain and
record the information included within the file table corresponding
to the media storage device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a protocol defined by the IEEE 1394-2000
standard.
FIG. 2 illustrates an exemplary IEEE 1394-2000 serial bus network
of devices including a video camera, a video cassette recorder, a
settop box, a television, a computer and audio/video hard disk
drives of the present invention.
FIG. 3 illustrates a block diagram of a media storage device
according to the preferred embodiment of the present invention.
FIG. 4 illustrates an exemplary IEEE 1394-2000 serial bus network
of devices including a separate dedicated storage array
controller.
FIG. 5 illustrates an exemplary file table corresponding to a first
portion of an audio/video (AV) file A recorded onto a first media
storage device.
FIG. 6 illustrates a file table corresponding to a second portion
of the AV file A recorded onto a second media storage device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Preferred Embodiment
File Tables
In a network of devices, including a plurality of media storage
devices, the media storage devices operate together to form an
automatically configuring storage array for storing and providing
streams of data, such as audio and video data. The operation of the
automatically configuring storage array of media storage devices is
seamless and transparent to the user and to other devices within
the network. When a record command is sent to any one of the media
storage devices within the automatically configuring storage array,
that media storage device will then determine the appropriate media
storage device to begin recording the stream of data. The record
command is forwarded to that device which will then begin recording
the stream of data. When the capacity within the current recording
media storage device is filled, the current recording media storage
device will broadcast a request over the network for any other
media storage device with available recording space to respond. The
current recording media storage device will then choose one of the
responding media storage devices, herein referred to as a next
available media storage device, and then notify the next available
media storage device of a time at which the next available media
storage device is to begin recording the stream of data. This
process continues until the entire stream of data is recorded and
the source device ceases transmitting.
The stream of data is preferably transmitted from a source device
on an isochronous channel over an IEEE 1394-2000 serial bus.
Communications between the media storage devices are preferably
sent on a separate isochronous communications channel over the IEEE
1394-2000 serial bus. Preferably, each of the media storage devices
include an isochronous data pipe which controls data storage and
retrieval operations, thereby transferring control and
communications between the available media storage devices.
Preferably, the media storage devices accept control instructions
directly from other devices within the network. Alternatively, a
separate control device within the network is utilized to provide a
control interface between the media storage devices and the other
devices within the network. Preferably, the media storage devices
are hard disk drives. Alternatively, any appropriate available
media storage device can be utilized within the automatically
configuring array of devices.
When recording a stream of data, each of the recording media
storage devices preferably uses a file system to facilitate
subsequent retrieval and playback of the recorded stream of data.
Utilizing this file system, when recording starts at a media
storage device, an indexed file table is generated that tracks the
storage location of the recorded stream of data on the media
storage device. The file table correlates each frame to its
location on the media storage device. Each frame is measured in
hours, minutes, seconds, and frames from the start of the stream of
data. This file table is stored on the media storage device and
associated with the stream of data. The file table also includes
information regarding where an earlier portion of the stream of
data is recorded, if appropriate, and where a subsequent portion of
the stream of data is recorded, if appropriate. When recording of
the stream of data is transferred to the next available media
storage device, a file table is generated by the next available
media storage device and associated with the portion of the stream
of data recorded on the next available media storage device. In
this manner, each media storage device that includes a recorded
portion of the stream of data also includes an associated file
table for the recorded portion of the stream of data. Using these
file tables, a search forward and backward through the recorded
stream of data can be accomplished to find a specific location
within the recorded stream of data. The file tables are also
utilized during retrieval of the recorded stream of data to
transfer control of the playback operation to the appropriate media
storage devices which were used to record the stream of data.
Preferably, when recording a stream of data from a source device,
redundancy techniques are utilized to ensure the integrity of the
recorded stream of data. This redundancy is used to prevent the
loss of data or facilitate the reconstruction of lost data if one
of the media storage devices within the automatically configuring
storage array is removed from the network of devices. If a media
storage device is removed, then the remaining media storage devices
will preferably automatically recreate the data that was stored on
the removed media storage device.
FIG. 2 illustrates an exemplary network of devices including a
video camera 28, a video cassette recorder (VCR) 30, a settop box
26, a television 24, a computer 20 and audio/video hard disk drives
(AVHDD) 32, 34 and 36 connected together by IEEE 1394-2000 cables
40, 42, 44, 46,48, 50 and 52. The IEEE 1394-2000 cable 50 couples
the video camera 28 to the VCR 30, allowing the video camera 28 to
send data, commands and parameters to the VCR 30 for recording. The
IEEE 1394-2000 cable 48 couples the VCR 30 to the AVHDD 32. The
IEEE 1394-2000 cable 46 couples the AVHDD 32 to the AVHDD 34. The
IEEE 1394-2000 cable 44 couples the AVHDD 34 to the computer 20.
The IEEE 1394-2000 cable 42 couples the computer 20 to the AVHDD
36. The IEEE 1394-2000 cable 40 couples the computer 20 to the
television 24. The IEEE 1394-2000 cable 52 couples the television
24 to the settop box 26.
The configuration illustrated in FIG. 2 is exemplary only. It
should be apparent that an audio/video network could include many
different combinations of components. The devices within such an
IEEE 1394-2000 network are autonomous devices, meaning that in an
IEEE 1394-2000 network, as the one illustrated in FIG. 2, in which
a computer is one of the devices, there is not a true
"master-slave" relationship between the computer and the other
devices. In many IEEE 1394-2000 network configurations, a computer
may not be present. Even in such configurations, the devices within
the network are fully capable of interacting with each other on a
peer basis. It should be recognized that data, commands and
parameters can be sent between all of the devices within the IEEE
1394-2000 network, as appropriate.
A block diagram of a hardware system resident in each AVHDD of the
preferred embodiment of the present invention is illustrated in
FIG. 3. The AVHDD 60 preferably includes an IEEE 1394-2000 serial
bus interface circuit 62 for sending communications to and
receiving communications from other devices coupled to the IEEE
1394-2000 serial bus network. The interface circuit 62 is coupled
to an isochronous data pipe 66. The isochronous data pipe 66
includes a register file 64. The isochronous data pipe 66 is
coupled to a buffer controller 68. The buffer controller 68 is also
coupled to a random access memory circuit 70 and to a read/write
channel circuit 72. The read/write channel circuit 72 is coupled to
media 74 on which data is stored within the AVHDD 60. The
read/write channel circuit 72 controls the storage operations on
the media 74, including reading data from the media 74 and writing
data to the media 74.
Each of the AVHDDs 32, 34 and 36 follow protocols which are
described herein and allow each of the AVHDDs 32, 34 and 36 to
coordinate activities with each of the other AVHDDs so that the
operation of the AVHDDs appears to a user and other components as a
single media storage device. In the preferred embodiment of the
present invention, the isochronous data pipe 66 within each of the
AVHDDs 32, 34 and 36 in the network of devices control the storage
operations of writing data to and reading data from the AVHDDs 32,
34 and 36. Alternatively, a separate controlling device is utilized
to monitor and control the activities of the AVHDDs 32, 34 and 36.
This controller can either be a device within the network, such as
the computer 20 or the settop box 26, or a separate dedicated
controller 80, as illustrated in FIG. 4.
In the embodiment illustrated in FIG. 4, the controller 80 is
coupled to the AVHDD 36 by the IEEE 1394-2000 cable 82. The
controller 80 includes an appropriate user interface which enables
a user to interact with the controller 80 and through the
controller 80 control the interconnected components within the
automatically configuring storage array. The controller 80 includes
the ability to recognize and control the AVHDDs 32, 34 and 36, as
well as sources of audio/video data such as the video camera 28,
the VCR 30, the television 24, the settop box 26 and the computer
system 20.
In the embodiment illustrated in FIG. 4, when the controller 80
receives an instruction to record an audio/video stream of data,
the controller 80 initiates the recording process utilizing the
AVHDDs 32, 34 and 36 available within the network of devices. After
receiving an instruction to record an audio/video stream of data,
the controller 80 locates the source of the data stream to be
recorded, such as the settop box 26, and instructs it to begin
transmitting the stream of data to be recorded on the IEEE
1394-2000 serial bus. The controller 80 obtains self describing
information embedded within the source device over the IEEE
1394-2000 serial bus. The controller 80 utilizes the self
describing information to locate the source device and learn how to
control the source device. The controller 80 then utilizes the AV/C
command set, appropriate for the source device, to control the
source device. The stream of data is transmitted in a digital
format over an isochronous channel on the IEEE 1394-2000 serial
bus.
After receiving an instruction to record an audio/video stream of
data, the controller 80 also locates one of the AVHDDs 32, 34 and
36 within the network, and instructs the selected one of the AVHDDs
32, 34 and 36 to begin recording the stream of data coming from the
source device. The controller 80 obtains self describing
information embedded within the selected AVHDD over the IEEE
1394-2000 serial bus. The controller 80 utilizes the self
describing information to locate the selected AVHDD and learn how
to control the selected AVHDD. In this embodiment, it does not
matter which one of the AVHDDs 32, 34 and 36, the controller 80
selects and instructs to record.
When the selected AVHDD receives the record instruction from the
controller 80, the selected AVHDD first determines if it has
available storage capacity, and if so, the selected AVHDD accepts
the record command. If the selected AVHDD determines that it does
not have available storage capacity, then the selected AVHDD
determines which one of the other AVHDDs within the network should
record the next stream of data. This determination is based on the
available capacity of each of the other AVHDDs and the current
responsibilities of those AVHDDs. Once the selected AVHDD
determines which one of the other AVHDDs will record this stream of
data, the selected AVHDD forwards the record command to that other
AVHDD, which will be referred to herein as the recording AVHDD. If
the selected AVHDD is not able to determine an available AVHDD,
then the selected AVHDD rejects the record command from controller
80.
Upon receiving the record command, the recording AVHDD then begins
recording the stream of data from the source device. If the
recording AVHDD runs out of available storage space while the
source device is still transmitting the stream of data, the
recording AVHDD sends a broadcast message to all AVHDDs within the
network requesting that any AVHDD with available storage capacity
respond. The recording AVHDD then selects one of the AVHDDs that
respond to the broadcast message as the next available AVHDD.
Preferably, the next available AVHDD is selected as the AVHDD with
the most available storage capacity of those AVHDDs that respond to
the broadcast message. The recording AVHDD then forwards the record
command to the next available AVHDD. When forwarding the record
command to the next available AVHDD, the recording AVHDD first
establishes the precise time at which it will run out of available
storage space and then forwards that time to the next available
AVHDD to indicate at which time the next available AVHDD must begin
recording the stream of data. The transfer of recording
responsibility is preferably accomplished without the loss of any
data. If the controller 80 then sends a subsequent command to the
selected AVHDD, the selected AVHDD will forward the command from
the controller 80 to the current recording AVHDD.
The control communications between the AVHDDs 32, 34 and 36 include
a real time component and a non-real time component. The non-real
time component utilizes AV/C commands and is used to communicate
such commands as record and play. This non-real time component is
sent using asynchronous transactions over the IEEE 1394-2000 serial
bus. The real time communications component is sent over the IEEE
1394-2000 serial bus on an isochronous communications channel and
utilizes the isochronous data pipe 66 within the AVHDDs 32, 34 and
36. This real time communications component is sent on an
isochronous channel which is different than the isochronous channel
on which the stream of data is transmitted. The currently recording
AVHDD continuously sends information over this isochronous
communications channel about itself. When the recording AVHDD
determines its available storage capacity is below a predetermined
threshold, the next available AVHDD is selected, and a transition
time at which the next available AVHDD is to initiate recording is
calculated by the recording AVHDD. The recording AVHDD transmits
over the isochronous communications channel to the next available
AVHDD the transition time and source of the stream of data to be
recorded.
Once the next available AVHDD begins recording the stream of data
at the designated transition time, it utilizes the non-real time
communications component to inform the prior recording AVHDD that
it is successfully recording the stream of data. In response to
this acknowledgment, the prior recording AVHDD stops transmitting
control data on the isochronous communications channel. When the
next available AVHDD recognizes that no control data is available
on the isochronous communications channel, it begins transmitting
control data on the isochronous communications channel as the
current recording AVHDD. Alternatively, the real-time
communications component is realized using scheduling algorithms,
as is well known in the art, which rely on recognizing the
transition from one recording AVHDD to the next AVHDD by watching
the IEEE 1394-2000 bus time.
In this alternate embodiment, the controller 80 can be implemented
as a separate device, as shown in FIG. 4, or a capable device
within the network, such as the settop box 26 or the computer 20,
can serve as the controller and be used to control the operation of
the AVHDDs 32, 34 and 36, within the network of devices.
In the preferred embodiment of the present invention, the
isochronous data pipes 66 within the AVHDDs 32, 34 and 36 in the
network can receive instructions directly from devices within the
network and are utilized to initiate and control the operation of
the AVHDDs 32, 34 and 36 during recording of a stream of data. When
the user desires to begin recording a stream of data, the user
enters a record command from any appropriate interface device
within the network, specifying the source device and the particular
stream of data to be recorded. The record command is then
transmitted to any one of the AVHDDs 32, 34 and 36 within the
network. The AVHDD which receives the record command then locates
the source of the data stream to be recorded and instructs this
source device to begin transmitting the stream of data on the IEEE
1394-2000 serial bus. The AVHDD also obtains self describing
information embedded within the source device over the IEEE
1394-2000 serial bus. The AVHDD utilizes the self describing
information to locate the source device and learn how to control
the source device. The AVHDD utilizes the AV/C command set
appropriate for the source device to control the source device. The
stream of data is transmitted in a digital format over an
isochronous channel on the IEEE 1394-2000 serial bus.
After receiving an instruction to record an audio/video stream of
data, the selected AVHDD then determines the recording AVHDD and
forwards the record command to that recording AVHDD. The recording
AVHDD then begins recording the stream of data from the source
device and will, if necessary, transfer control of recording to the
next available AVHDD, as described above.
When a stream of data is being recorded by a current recording
AVHDD, the isochronous data pipe 66 within that current recording
AVHDD controls the reception of the stream of data from the IEEE
1394-2000 serial bus and the transfer of that stream of data
through the read/write channel 72 and onto the media 74. If the
stream of data will exceed the available capacity of the AVHDD,
then the AVHDD determines when the media 74 within the AVHDD will
be filled, and then utilizes the isochronous data pipe 66 to
control the transfer of control to the next available AVHDD. The
process of determining the next available AVHDD will be discussed
in detail below. When transferring control from one AVHDD to
another, the current recording AVHDD contacts the next available
AVHDD utilizing the non-real time communications component and the
real time communications component, as described above, to inform
the next available AVHDD of the transition time when it will need
to begin recording the data stream. The next available AVHDD will
then begin recording the data stream at the appropriate transition
time.
When recording a stream of data, each of the AVHDDs use an internal
file system that includes file tables to serve as pointers and
connect a stream of data recorded over multiple AVHDDs. The file
tables are used during subsequent retrieval and playback of the
recorded stream of data. When recording starts at an AVHDD, a file
table is generated by the recording AVHDD. The file table is stored
on the recording AVHDD and associated with the portion of the
stream of data recorded on the recording AVHDD. The file table
includes a frame by frame index that correlates each frames'
running time within the stream of data to its storage location on
the AVHDD. The running time of each frame is measured in hours,
minutes, seconds, and frames from the start of the stream of data.
For example, the first frame of a stream of data is represented by
0 hours, 0 minutes, 0 seconds, and 1 frame. The file table includes
information about each frame of the portion of the recorded stream
of data stored on that particular AVHDD, as well as the device from
which recording control was transferred, if appropriate, and to
which device recording control was transferred, if appropriate. The
file tables form a list or map of a data stream recorded over
multiple AVHDDs.
A record command is issued by either the controller 80, the settop
box 26, the television 24, or the computer 20 and an initial
recording AVHDD is selected, as described above. For clarity, the
selected AVHDD is referred to as Disk 1. Disk 1 determines if it
has available storage capacity to record all, or a portion of, the
stream of data to be recorded. If Disk 1 determines that it has
available space, the record command is accepted. If Disk 1
determines that it does not have available space, then Disk 1
determines if another AVHDD has available storage space. If Disk 1
determines that another AVHDD has available storage space, then
Disk 1 accepts the record command, makes an appropriate entry in a
file table associated with the soon to be recorded stream of data,
and forwards the record command to the AVHDD determined to have
available storage space. If Disk 1 determines that it does not have
available storage space and is unable to locate another AVHDD with
available storage space, then the record command is rejected.
In this case, it is determined that Disk 1 has available storage
capacity and accepts the record command. When Disk 1 determines
that storage space is available, Disk 1 generates and stores a file
table associated with the soon to be recorded stream of data. For
clarity in describing this example, the soon to be recorded stream
of data is herein referred to as AV file A, and the file table
associated with AV file A is referred to as file A table. The AV
file A and file A table are stored on Disk 1.
FIG. 5 illustrates an exemplary file A table 100 corresponding to a
first portion of the AV file A recorded onto Disk 1. The file A
table 100 is preferably maintained by and recorded onto Disk 1.
Each frame within AV file A is identified by its running time as
measured from the start of the AV file A on Disk 1. If Disk 1 is
unable to record the entire AV file A and subsequent AVHDDs are
required to complete the recording of AV file A, then the running
time of each frame within AV file A, even a frame within a
subsequent portion of the AV file A recorded on a subsequent AVHDD,
is still measured from the start of the AV file A on Disk 1. The
file A table 100 includes columns 102-108 representing the running
time of each frame within AV file A recorded on Disk 1. Column 102
indicates the running time hours, column 104 indicates the running
time minutes, column 106 indicates the running time seconds, and
column 108 indicates the running time frames. A column 112
indicates the storage location address of each frame on the Disk 1
and a column 110 indicates the type of address indicated in column
112. Preferably, each frame within the AV file A recorded on Disk 1
is represented by a row entry on the file A table 100. Rows 114-120
are examples of four distinct file table entries. Row 114 indicates
the first frame of AV file A. The frame of row 114 is measured by
its running time relative the AV file A, in this case 0 hours, 0
minutes, 0 seconds, and 1 frame as indicated by columns 102-108.
LBA, or Logical Block Addressing, is a conventional hard disk
addressing scheme and indicates that the frame of row 114 is stored
at an LBA "0" on the Disk 1, as indicated in column 112. Row 116
indicates a randomly selected frame within the first portion of the
AV file A recorded on Disk 1. The frame of row 116 is measured by
its running time of 1 hour, 20 minutes, 12 seconds, and 6 frames
and is stored at an LBA "12345" within Disk 1. Row 118 indicates
the last frame within the first portion of the AV file A recorded
on Disk 1. This last frame can be either the last frame of the
entire AV file A, if the stream of data being recorded is
completed, or the last frame of the first portion of the AV file A
stored on Disk 1. The frame of row 118 is measured by its running
time of 2 hours, 25 minutes, 15 seconds, and 1 frame and is stored
at an LBA "23456" within Disk 1. The running time of the last frame
in row 118 is for illustrative purposes only. The actual running
time of a last frame on any AVHDD can be more or less than that
indicated in row 118, the actual running time of any last frame
will vary based on the length of an individual AV file or the
available storage space of the recording AVHDD.
Row 120 represents the frame immediately following the last frame
of AV file A recorded on Disk 1. Row 120 indicates to the Disk 1
that an additional portion of AV file A is recorded on another
AVHDD. Any file table associated with a stream of data that is
recorded over multiple AVHDDs includes a row entry similar to that
of row 120, unless the file table is associated with the last
portion of the stream of data to be recorded. The last frame of AV
file A recorded on Disk 1 is indicated in row 118 with a measured
running time of 2 hours, 25 minutes, 15 seconds, and 1 frame and
the frame immediately following is indicated in row 120 with a
measured running time of 2 hours, 25 minutes, 15 seconds, and 2
frames. The data type of the frame of row 120 is listed in column
110 as "DEVICE". DEVICE indicates to Disk 1 that the frame of row
120 is recorded on an AVHDD other than Disk 1. The location of this
other AVHDD is listed in column 112 of row 120 as "GUID B". GUID B
is the device identification of the other AVHDD within the IEEE
1394-2000 serial bus network that resumes recording of the AV file
A from where Disk 1 ran out of available storage and stopped
recording. For clarity in describing this example, the AVHDD
identified by GUID B is herein referred to as Disk 2.
FIG. 6 illustrates an exemplary file A table 200 corresponding to a
second portion of the AV file A recorded onto Disk 2. Disk 2
resumes recording the stream of data previously being recorded by
Disk 1. The structure of file A table 200 is the same as that of
file A table 100 in FIG. 5. The file A table 200 includes columns
202-208 representing the running time of each frame within the
second portion of the AV file A recorded on Disk 2. Column 202
indicates the running time hours, column 204 indicates the running
time minutes, column 206 indicates the running time seconds, and
column 208 indicates the running time frames. A column 212
indicates the storage location address of each frame and a column
210 indicates the type of address indicated in column 212.
Row 214 represents the frame immediately preceding the first frame
of the second portion of the AV file A recorded on Disk 2. Row 214
indicates to Disk 2 that a previous portion of the AV file A is
recorded on another AVHDD. Column 210 indicates that the frame of
row 214, with a measured running time of 2 hours, 25 minutes, 15
seconds, and 1 frame, is stored on a device other than Disk 2. The
location of this other device is listed in column 212 as "GUID A".
GUID A is the device identification for Disk 1. The frame
identified by columns 202-208 of row 214 matches the frame
identified by columns 102-108 of row 118 in FIG. 5, which is the
last frame of the first portion of AV file A recorded on Disk 1.
Row 216 indicates the first frame of the second portion of AV file
A recorded on Disk 2. The frame of row 216 is measured by its
running time of 2 hours, 25 minutes, 15 seconds, and 2 frames and
is stored at an LBA "123" within Disk 2. The frame identified by
columns 102-108 of row 120 in FIG. 5 matches the frame identified
by columns 202-208 of row 216 in FIG. 6, which is the first frame
of the second portion of AV file A recorded on Disk 2.
In this manner, Disk 1 is able to track the storage location of
each frame stored within Disk 1 as well as where a subsequent
portion of the stream of data is recorded. Similarly, Disk 2 is
able to track the storage location of each frame stored within Disk
2 as well as where a previous portion and a subsequent portion, if
appropriate, of the stream of data is recorded. Disk 1 and Disk 2
can store any number of different AV files, depending on storage
capacity, where each AV file stored on a particular disk will have
an associated file table similar to those illustrated in FIGS. 5
and 6.
Within the IEEE 1394-2000 serial bus network of the present
invention, one of the isochronous channels is allocated as a
broadcast channel. Each AVHDD coupled to the IEEE 1394-2000 serial
bus continually monitors the broadcast channel for any broadcast
messages. As the stream of data is recorded, the recording AVHDD
monitors its available storage capacity. When the storage capacity
is below a predetermined threshold, the recording AVHDD broadcasts
a message over the broadcast channel indicating that it is running
out of available storage space. Each AVHDD is programmed to respond
to this running-out-of-storage-space message if it has available
storage space. The response includes the unique device
identification of the responding AVHDD and can include relevant
information related to the responding AVHDD, for example the amount
of storage capacity available in the responding AVHDD. The
recording AVHDD receives responses from all responding AVHDDs and
appropriately chooses a next available AVHDD to continue recording
the stream of data once the recording AVHDD runs out of storage
space. The recording AVHDD can select the next available AVHDD to
continue recording based on most available storage space, first to
respond, or any other appropriate method of selection.
Using the file tables stored within the internal file system of
each AVHDD, a search forward and backward through the recorded
stream of data can be accomplished to find a specific location
within the recorded stream of data. The file tables are also
utilized during retrieval of the recorded stream of data to
transfer control of the playback operation to the appropriate
AVHDDs on which the stream of data is recorded. During a playback
operation, the data is initially retrieved from the desired
starting point within the recorded stream of data and transmitted
by the appropriate AVHDD to the requesting device over the IEEE
1394-2000 serial bus. When the ending point of the portion of the
recorded stream of data on the current AVHDD is reached, the buffer
controller 68 within that AVHDD reads the appropriate file table to
determine the AVHDD, within the network, on which the next portion
of the stream of data is recorded. Once the next AVHDD is
identified, the buffer controller 68 performs the non-real time
communications and the isochronous data pipe 66 performs the real
time communications, as described above, to that next AVHDD, in
order to ensure a seamless transition to the next AVHDD. In this
same manner, rewind and fast-forward capabilities are also
achieved, by following the file tables through the recorded stream
of data.
Preferably, the isochronous data pipe 66 in each of the AVHDDs is
utilized to control record and retrieval operations, as well as
communicate with the other AVHDDs within the automatically
configuring storage array of AVHDDs. The preferred embodiment of
the isochronous data pipe 66 is taught in U.S. patent application
Ser. No. 08/612,322, filed on Mar. 7, 1996 and entitled
"ISOCHRONOUS DATA PIPE FOR MANAGING AND MANIPULATING A HIGH-SPEED
STREAM OF ISOCHRONOUS DATA FLOWING BETWEEN AN APPLICATION AND A BUS
STRUCTURE," which is hereby incorporated by reference. The
isochronous data pipe 66 is programmable and will execute a series
of instructions on a stream of data in order to perform operations
and manipulations on the data as required to place the data in the
appropriate format.
In operation, when a user wants a particular stream of data
recorded, the user will program an instruction to record a
particular stream of data beginning immediately, or at some
specified later date. For example, a user could program an
instruction to record channel 10 from the settop box 26 between
7:00 PM and 8:00 PM. In the alternate embodiment, a record command
is generated and transmitted to the controller 80 corresponding to
the programmed instruction. The controller 80 then forwards the
record command to one of the AVHDDs 32, 34 and 36. In the preferred
embodiment, the corresponding record command is transmitted
directly to one of the AVHDDs 32,34 and 36. Once the record command
is received by one of the AVHDDs 32, 34 and 36, that AVHDD then
determines if it will accept the record command or determine which
one of the other AVHDDs should begin recording the stream of data.
The record command is then forwarded, if appropriate, to the
recording AVHDD. An instruction is also sent to the settop box 26,
to instruct it that it should transmit channel 10 between 7:00 PM
and 8:00 PM over the IEEE 1394-2000 serial bus. An isochronous
channel is used to transmit the source stream of data over the IEEE
1394-2000 serial bus from the settop box 26 to the recording
AVHDD.
The recording AVHDD begins recording the stream of data from the
settop box 26 and a file table is generated by and stored on the
recording AVHDD. The file table is associated with the portion of
the stream of data recorded on the recording AVHDD. The internal
file system of the recording AVHDD also stores the source of the
recorded stream of data and associates the source, the recorded
stream of data, and the file table. It should be clear that the
internal file system can also include additional relevant
information pertaining to the recorded stream of data. The file
table includes address locations of each frame of the portion of
the recorded stream of data stored on the recording AVHDD. The
recording AVHDD also begins transmitting control data over the
isochronous communications channel concerning itself and the
recorded stream of data. If the recording AVHDD does not have
enough capacity to record the entire stream of data from the settop
box 26, the recording AVHDD broadcasts a request for any AVHDD
within the network to respond if that AVHDD has available storage
capacity. From the responding AVHDDs, the recording AVHDD selects a
next available AVHDD as the AVHDD that will continue recording the
stream of data once the recording AVHDD runs out of storage
capacity. The recording AVHDD calculates a transition time at which
the next available AVHDD is to start recording and communicates the
transition time to the next available AVHDD over the isochronous
communications channel. At the designated transition time, the next
available AVHDD begins recording the stream of data and also
generates a file table with a first entry specifying from which
AVHDD control of the recoding was transferred. Subsequent entries
into the file table are recorded specifying the storage location of
each frame subsequently recorded onto the next available AVHDD.
Once the next available AVHDD begins recording the stream of data,
it utilizes the non-real time communications component to inform
the prior recording AVHDD that it is successfully recording the
stream of data. In response to this acknowledgment, the prior
recording AVHDD records an entry in its file table specifying to
which AVHDD control of the recording was transferred and stops
transmitting control data on the isochronous communications
channel. The next available AVHDD recognizes that no control data
is available on the isochronous communications channel and begins
transmitting control data on the isochronous communications channel
as the current recording AVHDD. This process is continued until the
entire data stream of the transmission of channel 10 between 7:00
PM and 8:00 PM from the settop box 26 is recorded.
When the user than wants to view the recorded stream of data, a
playback command is sent to the controller 80 in the alternate
embodiment or to one of the AVHDDs 32, 34 and 36, directly, in the
preferred embodiment. Once the playback command is received by one
of the AVHDDs 32, 34 and 36, the beginning of the stream of data is
located using the file tables associated with the stream of data
which serve as forward and backward pointers. Once the AVHDD on
which the beginning of the stream of data is located, that AVHDD
then begins transmitting the recorded stream of data over an
isochronous channel on the IEEE 1394-2000 serial bus to a specified
display device, such as the television 24. Control is transferred
between the AVHDDs, as specified by the file tables, in order to
transmit the recorded stream of data. Fast forward and rewind
functions, through the recorded stream of data, are also achieved
using the file tables stored in each AVHDD that includes portions
of the recorded stream of data.
The automatically configuring storage array of the present
invention includes a plurality of AVHDDs or other media storage
devices on which data can be recorded. The media storage devices
communicate with each other in order to store and retrieve streams
of data over multiple media storage devices, if necessary. To the
user and to the other devices within the network, the automatically
configuring storage array appears to be a single media storage
device. Accordingly, when a record or playback command is received
by any one of the media storage devices, the media storage devices
send control communications between themselves to ensure that the
stream of data is recorded or transmitted, as appropriate. Control
of the record or transmit operation is also transferred between the
media storage devices in order to utilize the full capacity of the
available media storage devices within the automatically
configuring storage array. Preferably, streams of data are also
recorded utilizing redundancy techniques in order to prevent the
loss of any recorded data. File tables associated with recorded
streams of data are utilized to facilitate search and retrieval of
the recorded streams of data throughout the media storage devices
within the automatically configuring storage array.
Alternative Embodiment
Embedded Object Descriptors
In an alternative embodiment, in a network of devices, including a
plurality of media storage devices, the media storage devices
operate together to form an automatically configuring storage array
for storing and providing streams of data, such as audio and video
data. The operation of the automatically configuring storage array
of media storage devices is seamless and transparent to the user
and to other devices within the network. When a record command is
sent to any one of the media storage devices within the
automatically configuring storage array, that media storage device
will then determine the appropriate media storage device to begin
recording the stream of data. The record command is forwarded to
that device which will then begin recording the stream of data.
When the capacity within the current recording media storage device
is filled, the current recording media storage device will
determine a next available media storage device and instruct that
next available media storage device to begin recording the stream
of data. This process continues until the stream of data is
recorded and the source device ceases transmitting.
In this alternative embodiment, the stream of data is transmitted
from a source device on an isochronous channel over an IEEE
1394-2000 serial bus. Communications between the media storage
devices are sent on a separate isochronous communications channel
over the IEEE 1394 -2000 serial bus. Also in this alternative
embodiment, each of the media storage devices include an
isochronous data pipe which controls data storage and retrieval
operations, thereby transferring control and communications between
the available media storage devices. The media storage devices in
this alternative embodiment accept control instructions directly
from other devices within the network. In a further alternate
embodiment, a separate control device within the network is
utilized to provide a control interface between the media storage
devices and the other devices within the network. The media storage
devices are hard disk drives. Alternatively, any appropriate
available media storage device can be utilized within the
automatically configuring array of devices.
When recording a stream of data, each of the recording media
storage devices use an embedded file system to facilitate
subsequent retrieval and playback of the recorded stream of data.
Utilizing this embedded file system, when recording starts at a
media storage device, an object descriptor is generated. This
object descriptor is stored on the media storage device and
associated with the stream of data. The object descriptor includes
information regarding where an earlier portion of the stream of
data is recorded, if appropriate, and where a subsequent portion of
the stream of data is recorded, if appropriate. Using these object
descriptors, a search forward and backward through the recorded
stream of data can be accomplished to find a specific location
within the recorded stream of data. The object descriptors are also
utilized during retrieval of the recorded stream of data to
transfer control of the playback operation to the appropriate media
storage devices which were used to record the stream of data.
Within this alternative embodiment, when recording a stream of data
from a source device, redundancy techniques are utilized to ensure
the integrity of the recorded stream of data. This redundancy is
used to prevent the loss of data or facilitate the reconstruction
of lost data if one of the media storage devices within the
automatically configuring storage array is removed from the network
of devices. If a media storage device is removed, then the
remaining media storage devices will automatically recreate the
data that was stored on the removed media storage device.
Referring to FIGS. 2 and 3, in this alternative embodiment, each of
the AVHDDs 32, 34 and 36 follow protocols which are described
herein and allow each of the AVHDDs 32, 34 and 36 to coordinate
activities with each of the other AVHDDs so that the operation of
the AVHDDs appears to a user and other components as a single media
storage device. The isochronous data pipe 66 within each of the
AVHDDs 32, 34 and 36 in the network of devices control the storage
operations of writing data to and reading data from the AVHDDs 32,
34 and 36. As described above, a separate controlling device can
also be utilized to monitor and control the activities of the
AVHDDs 32, 34 and 36. This controller can either be a device within
the network, such as the computer 20 or the settop box 26, or a
separate dedicated controller 80, as illustrated in FIG. 4.
In the embodiment illustrated in FIG. 4, the controller 80 is
coupled to the AVHDD 36 by the IEEE 1394-2000 cable 82. The
controller 80 includes an appropriate user interface which enables
a user to interact with the controller 80 and through the
controller 80 control the interconnected components within the
automatically configuring storage array. The controller 80 includes
the ability to recognize and control the AVHDDs 32, 34 and 36, as
well as sources of audio/video data such as the video camera 28,
the VCR 30, the television 24, the settop box 26 and the computer
system 20.
In the embodiment illustrated in FIG. 4, when the controller 80
receives an instruction to record an audio/video stream of data,
the controller 80 initiates the recording process utilizing the
AVHDDs 32, 34 and 36 available within the network of devices. After
receiving an instruction to record an audio/video stream of data,
the controller 80 locates the source of the data stream to be
recorded, such as the settop box 26, and instructs it to begin
transmitting the stream of data to be recorded on the IEEE
1394-2000 serial bus. The controller 80 obtains self describing
information embedded within the source device over the IEEE
1394-2000 serial bus. The controller 80 utilizes the self
describing information to locate the source device and learn how to
control the source device. The controller 80 then utilizes the AV/C
command set, appropriate for the source device, to control the
source device. The stream of data is transmitted in a digital
format over an isochronous channel on the IEEE 1394-2000 serial
bus.
After receiving an instruction to record an audio/video stream of
data, the controller 80 also locates one of the AVHDDs 32, 34 and
36 within the network, and instructs the selected one of the AVHDDs
32, 34 and 36 to begin recording the stream of data coming from the
source device. The controller 80 obtains self describing
information embedded within the selected AVHDD over the IEEE
1394-2000 serial bus. The controller 80 utilizes the self
describing information to locate the selected AVHDD and learn how
to control the selected AVHDD. In this embodiment, it does not
matter which one of the AVHDDs 32, 34 and 36, the controller 80
selects and instructs to record.
In this alternative embodiment, when the selected AVHDD receives
the record instruction from the controller 80, the selected AVHDD
first determines which one of the available AVHDDs within the
network should record the next stream of data. This determination
is based on the available capacity of each of the available AVHDDs
and the current responsibilities of those AVHDDs. Once the selected
AVHDD determines which one of the available AVHDDs will record this
stream of data, the selected AVHDD forwards the record command to
that available AVHDD, which will be referred to herein as the
recording AVHDD. The recording AVHDD then begins recording the
stream of data from the source device. If the recording AVHDD runs
out of available storage space while the source device is still
transmitting the stream of data, the recording AVHDD, will locate
the next available AVHDD within the network and forward the record
command to that AVHDD. When forwarding the record command to the
next available AVHDD, the recording AVHDD first establishes the
precise time at which it will run out of available storage space
and at which time the next available AVHDD must begin recording the
stream of data. The transfer of recording responsibility is
preferably accomplished without the loss of any data. If the
controller 80 then sends a subsequent command to the selected
AVHDD, the selected AVHDD will forward the command from the
controller 80 to the current recording AVHDD.
The control communications between the AVHDDs 32, 34 and 36 include
a real time component and a non-real time component. The non-real
time component utilizes AV/C commands and is used to communicate
such commands as record and play. This non-real time component is
sent using asynchronous transactions over the IEEE 1394-2000 serial
bus. The real time communications component is sent over the IEEE
1394-2000 serial bus on an isochronous communications channel and
utilizes the isochronous data pipe 66 within the AVHDDs 32, 34 and
36. This real time communications component is sent on an
isochronous channel which is different than the isochronous channel
on which the stream of data is transmitted. The currently recording
AVHDD continuously sends information over this isochronous
communications channel about itself. One isochronous cycle before
the time of the transition from the currently recording AVHDD to
the next available AVHDD, the currently recording AVHDD changes the
information transmitted on the isochronous communications channel
to provide that the next available AVHDD is the current recording
AVHDD. In response, the next available AVHDD then begins recording
the stream of data on the next isochronous cycle.
Once the next available AVHDD begins recording the stream of data,
it utilizes the non-real time communications component to inform
the prior recording AVHDD that it is successfully recording the
stream of data. In response to this acknowledgment, the prior
recording AVHDD stops transmitting control data on the isochronous
communications channel. When the next available AVHDD recognizes
that no control data is available on the isochronous communications
channel, it begins transmitting control data on the isochronous
communications channel as the current recording AVHDD.
Alternatively, the real-time communications component is realized
using scheduling algorithms, as is well known in the art, which
rely on recognizing the transition from one recording AVHDD to the
next AVHDD by watching the IEEE 1394-2000 bus time.
In this alternate embodiment, the controller 80 can be implemented
as a separate device, as shown in FIG. 4, or a capable device
within the network, such as the settop box 26 or the computer 20,
can serve as the controller and be used to control the operation of
the AVHDDs 32, 34 and 36, within the network of devices.
In this embodiment of the present invention, the isochronous data
pipes 66 within the AVHDDs 32, 34 and 36 in the network can receive
instructions directly from devices within the network and are
utilized to initiate and control the operation of the AVHDDs 32, 34
and 36 during recording of a stream of data. When the user desires
to begin recording a stream of data, the user enters a record
command from any appropriate interface device within the network,
specifying the source device and the particular stream of data to
be recorded. The record command is then transmitted to any one of
the AVHDDs 32, 34 and 36 within the network. The AVHDD which
receives the record command then locates the source of the data
stream to be recorded and instructs this source device to begin
transmitting the stream of data on the IEEE 1394-2000 serial bus.
The AVHDD also obtains self describing information embedded within
the source device over the IEEE 1394-2000 serial bus. The AVHDD
utilizes the self describing information to locate the source
device and learn how to control the source device. The AVHDD
utilizes the AV/C command set appropriate for the source device to
control the source device. The stream of data is transmitted in a
digital format over an isochronous channel on the IEEE 1394-2000
serial bus.
After receiving an instruction to record an audio/video stream of
data, the receiving AVHDD then determines the next available AVHDD
and forwards the record command to that next available AVHDD. The
next available AVHDD then begins recording the stream of data from
the source device and will, if necessary, transfer control of
recording to the next available AVHDD, as described above.
Within the alternate embodiment, when a stream of data is being
recorded by a current recording AVHDD, the isochronous data pipe 66
within that current recording AVHDD controls the reception of the
stream of data from the IEEE 1394-2000 serial bus and the transfer
of that stream of data through the read/write channel 72 and onto
the media 74. If the stream of data will exceed the available
capacity of the AVHDD, then the AVHDD determines when the media 74
within the AVHDD will be filled, and then utilizes the isochronous
data pipe 66 to control the transfer of control to the next
available AVHDD. When transferring control from one AVHDD to
another, the current AVHDD contacts the next available AVHDD
utilizing the non-real time communications component and the real
time communications component, as described above, to inform the
next available AVHDD when it will need to begin recording the data
stream. The next available AVHDD will then begin recording the data
stream at the appropriate time.
In this alternative embodiment, when recording a stream of data,
each of the AVHDDs use an embedded file system and object
descriptors to serve as pointers and connect a stream of data
recorded over multiple AVHDDs. The embedded file system and object
descriptors are used during subsequent retrieval and playback of
the recorded stream of data. When recording starts at an AVHDD, an
object descriptor is generated by the recording AVHDD. The object
descriptor is stored on the media storage device and associated
with the stream of data. The object descriptor includes information
about the recorded stream of data, including the device from which
recording control was transferred, if appropriate, and to which
device recording control was transferred, if appropriate. The
object descriptors form a list or map of a data stream recorded
over multiple AVHDDs.
Using the object descriptors stored with the data, a search forward
and backward through the recorded stream of data can be
accomplished to find a specific location within the recorded stream
of data. The object descriptors are also utilized during retrieval
of the recorded stream of data to transfer control of the playback
operation to the appropriate AVHDDs on which the stream of data is
recorded. During a playback operation, the data is initially
retrieved from the desired starting point within the recorded
stream of data and transmitted by the appropriate AVHDD to the
requesting device over the IEEE 1394-2000 serial bus. When the
ending point of the recorded stream of data on the current AVHDD is
reached, the buffer controller 68 within that AVHDD reads the
appropriate object descriptor to determine the AVHDD, within the
network, on which the next portion of the stream of data is
recorded. Once the next AVHDD is identified, the buffer controller
68 performs the non-real time communications and the isochronous
data pipe 66 performs the real time communications, as described
above, to that next AVHDD, in order to ensure a seamless transition
to the next AVHDD. In this same manner, rewind and fast-forward
capabilities are also achieved, by following the object descriptors
through the recorded stream of data.
The isochronous data pipe 66 in each of the AVHDDs is utilized to
control record and retrieval operations, as well as communicate
with the other AVHDDs within the automatically configuring storage
array of AVHDDs. The isochronous data pipe 66 is programmable and
will execute a series of instructions on a stream of data in order
to perform operations and manipulations on the data as required to
place the data in the appropriate format.
In the operation of this alternative embodiment, when a user wants
a particular stream of data recorded, the user will program an
instruction to record a particular stream of data beginning
immediately, or at some specified later date. For example, a user
could program an instruction to record channel 10 from the settop
box 26 between 7:00 PM and 8:00 PM. In the embodiment illustrated
in FIG. 4, a record command is generated and transmitted to the
controller 80 corresponding to the programmed instruction. The
controller 80 then forwards the record command to one of the AVHDDs
32, 34 and 36. In the embodiment illustrated in FIG. 2, the
corresponding record command is transmitted directly to one of the
AVHDDs 32, 34 and 36. Once the record command is received by one of
the AVHDDs 32, 34 and 36, that AVHDD then determines which one of
the available AVHDDs 32, 34 and 36 should begin recording the
stream of data. The record command is then forwarded, if
appropriate, to the recording AVHDD. An instruction is also sent to
the settop box 26, to instruct it that it should transmit channel
10 between 7:00 PM and 8:00 PM over the IEEE 1394-2000 serial bus.
An isochronous channel is used to transmit the source stream of
data over the IEEE 1394-2000 serial bus from the settop box 26 to
the recording AVHDD.
The recording AVHDD begins recording the stream of data from the
settop box 26. At the beginning of the recorded stream of data, an
object descriptor is recorded specifying that this is the beginning
of the recorded stream of data and from where the recorded stream
of data is received. The recording AVHDD also begins transmitting
control data over the isochronous communications channel concerning
itself and the recorded stream of data. If the recording AVHDD does
not have enough capacity to record the entire stream of data from
the settop box 26, then one isochronous cycle before the necessary
time of transition, the currently recording AVHDD changes the
information transmitted on the isochronous communications channel
to provide that the next available AVHDD is the current recording
AVHDD. In response to this communications information, the next
available AVHDD begins recording the stream of data on the next
isochronous cycle. At the beginning of this recorded portion of the
stream of data, the next available AVHDD records an object
descriptor specifying the source of the stream of data and from
which AVHDD control of the recording was transferred.
Once the next available AVHDD begins recording the stream of data,
it utilizes the non-real time communications component to inform
the prior recording AVHDD that it is successfully recording the
stream of data. In response to this acknowledgment, the prior
recording AVHDD stops transmitting control data on the isochronous
communications channel. The next available AVHDD recognizes that no
control data is available on the isochronous communications channel
and begins transmitting control data on the isochronous
communications channel as the current recording AVHDD. This process
is continued until the entire data stream of the transmission of
channel 10 between 7:00 PM and 8:00 PM from the settop box 26 is
recorded.
When the user than wants to view the recorded stream of data, a
playback command is sent to the controller 80 in the embodiment
illustrated in FIG. 4 or to one of the AVHDDs 32, 34 and 36,
directly, in the embodiment illustrated in FIG. 2. Once the
retrieval command is received by one of the AVHDDs 32, 34 and 36,
the beginning of the stream of data is located using the object
descriptors stored with the stream of data which serve as
forward-and backward pointers. Once the AVHDD on which the
beginning of the stream of data is located, that AVHDD then begins
transmitting the recorded stream of data over an isochronous
channel on the IEEE 1394-2000 serial bus to a specified display
device, such as the television 24. Control is transferred between
the AVHDDs, as specified by the object descriptors, in order to
transmit the recorded stream of data. Fast forward and rewind
functions, through the recorded stream of data, are also achieved
using the object descriptors stored within the recorded stream of
data.
The automatically configuring storage array of the alternate
embodiment of the present invention includes a plurality of AVHDDs
or other media storage devices on which data can be recorded. The
media storage devices communicate with each other in order to store
and retrieve streams of data over multiple media storage devices,
if necessary. To the user and to the other devices within the
network, the automatically configuring storage array appears to be
a single media storage device. Accordingly, when a record or
playback command is received by any one of the media storage
devices, the media storage devices send control communications
between themselves to ensure that the stream of data is recorded or
transmitted, as appropriate. Control of the record or transmit
operation is also transferred between the media storage devices in
order to utilize the full capacity of the available media storage
devices within the automatically configuring storage array. Streams
of data are also recorded utilizing redundancy techniques in order
to prevent the loss of any recorded data. Object descriptors are
also stored with recorded streams of data in order to facilitate
search and retrieval of the recorded streams of data throughout the
media storage devices within the automatically configuring storage
array.
Redundancy
In the preferred embodiment of the present invention, when a stream
of data is recorded within the automatically configuring storage
array, the stream of data is recorded using a level of redundancy
in order to ensure the integrity of the recorded data and prevent
any loss of data. This redundancy is used to prevent the loss of
data and facilitate the reconstruction of lost data when one of the
AVHDDs within the automatically configuring storage array of the
present invention is removed from the network of devices or
otherwise becomes unavailable. Using a redundancy technique, if a
media storage device is removed, then the remaining AVHDDs will
preferably automatically recreate and record the data that was
stored on the removed AVHDD.
Any available redundancy techniques can be used to store a stream
of data within the automatically configuring storage array of the
present invention. In such redundancy techniques, data or
relationships among data, are stored in multiple locations. In one
such technique, data is mirrored or duplicated and stored in two
separate areas of the storage array. Using a mirror technique, two
separate copies of the data are stored in different locations
within the automatically configuring storage array. This method has
the disadvantage of requiring more storage capacity within the
array, but there is a high probability of recreating any lost
data.
Using a parity redundant technique, a portion of the memory storage
array is dedicated to storing redundant data. The size of this
redundant portion is less than the remaining space within the array
used to store the actual data. In an array including five AVHDDs,
one of the AVHDDs could be dedicated as the parity AVHDD. This
method requires less capacity than the mirror technique, but also
has a lower probability of recreating any lost data.
Preferably, some level of redundancy techniques are used to record
data within the automatically configuring storage array of the
present invention. Such techniques are generally referred to as
redundant array of independent disks (RAID) techniques. The term
RAID means a disk array in which part of the physical storage
capacity is used to store redundant information about data stored
on the remainder of the storage capacity. This redundant
information enables regeneration of user data in the event that one
of the AVHDDs within the array is removed or fails. A detailed
discussion of RAID systems is found in a book entitled "The
RAIDBook: Sixth Edition," published by the RAID Advisory Board,
North Grafton, Mass.
The present invention has been described in terms of specific
embodiments incorporating details to facilitate the understanding
of principles of construction and operation of the invention. Such
reference herein to specific embodiments and details thereof is not
intended to limit the scope of the claims appended hereto. It will
be apparent to those skilled in the art that modifications may be
made in the embodiment chosen for illustration without departing
from the spirit and scope of the invention. Specifically, it will
be apparent to those skilled in the art that while the preferred
embodiment of the present invention is used with an IEEE 1394-2000
serial bus structure, the present invention could also be
implemented on any other appropriate bus structures. Additionally,
it will also be apparent that while the preferred embodiment of the
present invention includes AVHDDs within the automatically
configuring storage array, any other appropriate media storage
device can also be used.
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